Pickup and circuit for stringed musical instrument



1969 YOSHIKAZU KAWABATA ET AL 3,472,943

PICKUP AND CIRCUITFOR STRINGED MUSICAL INSTRUMENT Filed Oct. 11, 1966 2Sheets-Sheet l FIG.

FIG. 3 (b) FIG. 3(a) FIG. 5 PRIOR ART Oct. 14, 1969 yos KAWABATA ET AL3,472,943

PICKUP AND CIRCUIT FOR STRINGED MUSICAL INSTRUMENT Filed Oct. 11, 1966 2Sheets-$heet 2 n2? 30 FIG. 6

0 LQQ :HHHQHHH H IIIIIIIIIIIIM] 0 United States Patent- Office 3,472,943Patented Oct. 14, 1969 US. Cl. 841.15 4 Claims ABSTRACT OF THEDISCLOSURE In an electric guitar, a pickup device comprising twoelectric pickup elements disposed at different positions along guitarstrings and each having a pickup coil with two terminals, and twovariable resistors with two fixed terminals and a movable terminal, twoterminals of each of the coils being connected to two fixed terminals ofeach of the resistors, one side of one of the coils being grounded, themovable terminal of the resistors connected thereto being connected tothe one side of the other of the coils, and the resulting output signalbeing led out from the movable terminal of the resistor connected tosaid other of the coils.

This invention relates to electric stringed musical instruments and moreparticularly to a new and imrpoved pickup device comprising,essentially, two pickup elements and an electrical circuit operating toproduce, in a simulated manner, the effect of continuously shifting thepositions of the two pickup elements (hereinafter referred to aspickups) which pick up the vibrations of strings in an electric stringedmusical instrument without actual mechanical shifting of the pickups.

In an electric stringed musical instrument such as an electric guitar, arequirement arising from the playing thereof is that the tone color bewidely variable. To meet this requirement, it has been the conventionalpractice to provide a plurality of pickups in respectively differentpositions with respect to the longitudinal direction of each string andto pick up the vibration of the string at these different positions. Inknown devices for this practice, the range of variation of the tonecolors has been limited because of the nature of these devices, which,moreover, have been accompanied by further difiiculty as will bedescribed hereinafter.

It is an object of the present invention to overcome these difficultiesby providing, in an electric stringed musical instrument, a pickupdevice of simple composition and arrangement whereby tone colorvariation can be accomplished gradually and continuously from hard tonesto soft tones and vice versa without mechanical movement of pickupsrelative to the strings.

More specifically, an object of the invention is to provide a pickupdevice of the above stated character comprising pickups and a pickupcircuit whereby an effect equivalent to the continuous shifting of thepositions of the pickups can be obtained electrically without mechanicalshifting of the pickups relative to the strings of the musicalinstrument.

According to the present invention, briefly stated, there is provided,in an electric stringed musical instrument, a pickup device comprisingtwo pickups disposed at respectively different positions with respect tothe length-wise direction of the strings of the instrument to receivevibrations thereof and produce respective outputs in response to thevibrations and a pickup circuit connected to the pickups and includingone or two variable resistors connected differentially with respect tosaid respective outputs of said pickups, which are thereby continuouslychanged over and led out.

The nature, principle, and details of the invention will be more clearlyapparent from the following detailed description principally withrespect to preferred embodiments of the invention, when read inconjunction with the accompanying drawings, in which like parts aredesignated by like reference numerals and characters.

In the drawings:

FIG. 1 is a plan view showing the face side of an electric guitar towhich one embodiment of the invention has been applied.

FIG. 2 is a diagram, partly in schematic form and partly in structuralform, showing the important parts of the pickup system of the guitarshown in FIG. 1;

FIG. 3(a) is a schematic diagram showing an essential part of the pickupsystem shown in FIG. 2;

FIG. 3(b) is a schematic diagram similar to FIG. 3(a), showing anarrangement wherein the first pickup coil and the second pickup coilshown in FIG. 3(a) are interchanged;

FIGS. 4 and 5 are schematic diagrams showing examples of known pickupdevices;

FIG. 6 is a plan view showing the face side of an electric bass guitarto which an embodiment of the invention has been applied;

FIG. 7 is a diagram, partly in schematic form and partly in structuralform, showing the important parts of the pickup system of the guitarshown in FIG. 8; and

FIGS. 8 and 9 are schematic diagrams showing the essential parts offurther embodiments of the invention.

As conducive to a full appreciation of the novelty and utility of thepresent invention, the following brief consideration of examples of theprior art is presented.

As shown in FIG. 4 as mentioned briefly hereinbefore, it has been theconventional practice to provide a plurality of pickups 2 and 3 atdifferent positions with respect to each string 1. The outputs of thepickups 2 and 3 are appropriately selected by switches 4 and 5 and ledout. Alternatively, for example, as shown in FIG. 5 two pickups 2 and 3are connected in series, and a variable resistor 6 is inserted as ashunt across one of the pickups, e.g., pickup 3, thereby to vary thetone color by varying the quality factor, Q, of the coil of the pickup3.

In a device of the above described composition and arrangement, therange of variation of the tone colors is naturally limited.Theoretically, it is possible to vary tone colors over a wide range and,moreover, into many kinds by providing a large number of pickups atrespectively different positions. Furthermore, it is possible to obtaincontinuous or stepless variation by causing each pickup position toshift continuously. Such expedients, however, give rise to extremecomplications, which are disadvantageous.

The present invention contemplates the provision of a pickup and circuitdevice of simple composition and arrangement wherein, by the use of anelectrical circuitry, an effect equivalent to continuous shifting ofpickups can be obtained without actual mechanical movement of thepickups.

Referring to FIG. 1 illustrating one example of embodiment of theinvention, the guitar 20 has a control circuit as shown in FIG. 2 and isconnected to the input terminal of a guitar amplifier (not shown)provided separately from the guitar by a cord (also not shown) which isplugged into a jack 30 on the panel 21 of the body of the guitar 20.This example illustrates the application of the invention to an electricguitar in which three electromagnetic pickups are used, and in whichstrings 11, 12,

13, 14, 15, and 16 are strung in the known manner, being supported on abridge 31.

One pickup 22 is positioned relatively closely to the bridge 31, whilethe second pickup 23 is positioned relatively apart from the bridge 31.The third pickup 24 is positioned even farther than pickup 23 from thebridge 31. Each of the pickups 22, 23, and 24 comprises coils of severalthousands of turns of winding wound around pole pieces (22A, 22B, 22C,22D, 22E, and 22F in the case of pickup 22, for example) which aredisposed to confront from below, respectively, strings 11 through 16,inclusive.

Since the six strings 11 through 16, inclusive, are made of magneticmaterial, when each string is caused by the playing of the guitar tovibrate, voltages in accordance with the resulting vibration signal areinduced in the pickups 22, 23, and 24.

One terminal of the coil of pickup 24 is grounded, while the otherterminal is connected to one fixed contact terminal b of athree-position switch 25. The coils of pickups 22 and 23 are connectedto the other fixed contact terminal a of the switch 25 by way of gangedvariable resistors 26 by which these coils are mutually coupled, Thisswitch 25 is mounted on the panel 21 of the guitar body and, while theguitar is being played, can be manually switched in a simple mannerbetween three positions, that is, three positions for causing the movingcontact me of the switch to contact only the contact a, both contacts aand b, and only the contact b. Thus, by this switching it is possible toselect in a simple manner one state from among three connection states,i.e., that wherein only pickup 24 is connected, that wherein onlypickups 22 and 23 are connected, and that wherein both pickup 24 andpickups 22 and 23 are simultaneously connected.

The circuit after the switch 25 is of a commonly used type in whichthere are provided a variable resistor 28 of B type or A type ofapproximately 500 kilo-ohms, a variable resistor 27 of A type ofapproximately 500 kilo-ohms, and a 0.01-microfarad capacitor 29connected to the movable terminal 27A of the variable resistor 27.

Referring to FIG. 3(a) showing the essential parts of the device shownin FIG. 2, the aforementioned ganged variable resistor 26 comprises anA-type, 2S0-kilo-ohm variable resistor 26D and a C-type, 250-kilo-ohmvariable resistor 26B, whose respective movable terminals 26C and 26Aare adapted to move in an intercoupled manner in the same direction asviewed in FIG. 3(a).

The two terminals of the coil of pickup 23 are connected to the twoterminals of the variable resistor 26D, while the two terminals of thecoil of pickup 22 are connected to the two terminals of the variableresistor 26B. The side of one terminal 2 of the variable resistor 26D isgrounded. The output of pickup 23 is led by way of the movable terminal260 of the variable resistor 26D to the side of one terminal d of thevariable resistor 26B. The outputs of the two pickups 22 and 23 are ledout through the movable terminal 26A of the variable resistor 26B.

When the movable terminals 26A and 26C of the ganged variable resistors26 are moved to the side of terminals d and f, the output from pickup 23is obtainable, and when these movable terminals 26A and 26C are moved tothe side of terminals c and e, the output from pickup 22 is obtainable.At an intermediate position between terminals c and d terminals e and 7,an output mixture of the outputs of both pickups is obtainable, theproportions of the outputs in the mixture being in accordance with theintermediate position.

This ganged variable resistor 26 is installed in the body of the guitarand can be operated in a simple manner by a control knob 26N mounted onthe panel 21 as shown in FIG. 1. Accordingly, even during playing of theguitar, an effect equivalent to an apparent movement of the positions ofthe pickups can be obtained in a simple manner.

In another embodiment of the invention as shown in FIG. 3(b), thepositions of pickups 22a and 23a are reversed relative to those ofpickups 22 and 23 in the arrangement illustrated in FIG. 3(a) in respectto the relative distances of the two pickups from the bridge 31. Inother words, interchanging of the positions of the pickups 22 and 23together with their respective associated parts of the ganged variableresistor 26 in the arrangement of FIG. 3(a) results in the arrangementof FIG. 3(b). In other respects, the two examples are alike, and theabove description set forth with reference to FIG. 3(a) is applicablealso to the example shown in FIG. 3(b).

FIG. 6 shows a bass guitar to which an example of the invention ofimproved form is applied. This guitar is a four-string instrument inwhich two pickups 122 and 123 are used, and which is approximatelyequivalent to the guitar shown in FIG. 1 from which pickup 24 shown inFIGS. 1 and 2 has been removed. While this embodiment of the inventionwill be described with respect to its application to a bass guitar, itwill be obvious that this embodiment can be applied also to an electricguitar as shown in FIG. 1.

This example shown in FIGS. 6 and 7 incorporates improvements for thecase where, in embodying the circuit of FIG. 3, relatively large numbersof winding turns of the pickup coils are required, that is, the casewhere the stray capacitances of the pickups and the resistancecomponents at the intermediate positions of the movable terminals 26Aand 26C of the variable resistors 26 constitute low-pass filters wherebythe high-frequency components of the signals are attenuated.

The essential parts according to the invention of the guitar shown inFIG. 6 are shown in FIG. 7. The essential parts and their arrangementshown are the same as those shown in FIG. 3 except for the provision ofcapacitors 132 and 133. The capacitor 132 is connected between the side0 of the coil of pickup 122 and the movable terminal 126A of variableresistor 126B, while the capacitor 133 is connected between the side 7of the coil of pickup 123 and the movable terminal 1260 of variableresistor 126D. The electrostatic capacitances of these capacitors areeach 0.003 microfarad in the example shown.

When, with the capacitors 132 and 133 connected in this manner, thevariable resistors are moved, and their movable terminals 126A and 126Care respectively placed at the terminals 0 and e, the pickup 122 is notaifected by capacitor 132. On the other hand, when these movableterminals are respectively placed at terminals d and f, the pickup 123is unaffected by capacitor 133. Thus, at these terminal positions of themovable terminals 126A and 126C, signal voltages induced by thevibration of each string can be led out with the pickups in theirrespective unaffected states.

However, when the movable terminals of the ganged variable resistors 126are in intermediate positions between terminals c and d and terminals eand f, the capacitors 132 and 133 are placed into effective states. As aresult of the addition of these capacitors 132 and 133, the respectivehigh-frequency components of the signal voltages of pickups 122 and 123are not attenuated and fully appear on the output side even when theganged variable resistor is in an intermediate position. The resultingreproduced sounds, supplemented by the high-frequency components, becomebrilliant and strong sounds.

In a further embodiment of the invention as shown in FIG. 8, a pluralityof fixed resistors 36A and 36B and intercoupled-type selector switches35A and 35B are used in place of the ganged variable resistors of theexample illustrated in FIG. 3a. In this pickup system, it is notpossible to obtain continuous or stepless variations of tone color asare obtainable by the use of a ganged variable resistor as illustratedin FIG. 3(a), but a plurality of suitable combinations of tone colorscan be selectively prepared beforehand and, during playing, selected ina simple manner.

More specifically, when the selector switches 35A and 35B are switchedto the taps designated by v and w on the side, output from pickup 22 isobtainable, and when these switches are switched to taps x and y on theother side, output from pickup 23 is obtainable. At intermediate, taps,a mixture of the outputs of the two pickups 22 and 23 in proportionscorresponding to the tap position is obtainable. Accordingly, byoperating the intercoupled changeover switches 35A and 35B, it ispossible to obtain the same effect as that obtainable by the use of alarge number of pickups.

Furthermore, a modification as illustrated in FIG. 8 can be produced byadding capacitors as described hereinbefore with reference to FIG. 7 tothe circuit shown in FIG. 8.

As described above, the present invention provides, in an electricstringed musical instrument, a novel pickup device of simple circuitcomposition and arrangement whereby tone color variation can beaccomplished gradually and, moreover, continuously from hard tones tosoft tones and, conversely, from soft tones to hard tones withoutmechanical movement of the pickup elements relative to the strings.Thus, by the practice of the invention, it is possible to obtain aneffect, unattainable heretofore, which is equivalent to that produced bymechanical movement of the positions of the pickup elements relative tothe strings.

It should be understood, of course, that the foregoing disclosurerelates to only preferred embodiments of the invention and that it isintended to cover all changes and modifications of the examples of theinvention herein chosen for the purposes of the disclosure, which do notconstitute departures from the spirit and scope of the invention as setforth in the appended claims.

What we claim is:

1. In an electric stringed musical instrument, a pickup devicecomprising two pickup elements disposed at respectively differentpositions with respect to the lengthwise direction of the strings of theinstrument to receive vibrations thereof and produce respective outputsin response to said vibration, and a pickup circuit connected to thepickup elements and including at least one variable resistor connecteddifferentially with respect to said respective outputs of said pickupelements whereby said respective outputs are continuously changed overand led out, each pickup element having a pickup coil with two terminalsconnected respectively to the fixed terminals of a respective one of twomutually intercoupled variable resistors, the negative side of one ofthe pickup coils be ing grounded, the movable terminal of the variableresistor connected thereto being connected to the negative side of theother pickup coil, the resulting output being led out from the movableterminal of the variable resistor connected to said other pickup coil.

2. The pickup device as claimed in claim 1, in which a capacitor isconnected between the signal lead-out side of each pickup coil and themovable terminal of each of the two variable resistors.

3. The pickup device as claimed in claim 1, which each variable resistorcomprises a plurality of fixed resistors between the fixed terminalsthereof and a selector switch having a movable terminal and a pluralityof fixed terminals connected to respective junction terminals of thefixed resistors whereby the resulting output is led out.

4. The pickup device as claimed in claim 3, in which a capacitor isconnected between the signal lead-out side of each pickup coil and themovable terminal of the corresponding selector switch.

References Cited UNITED STATES PATENTS 2,784,631 3/1957 Fender 841.163,194,870 7/1965 Tondreau et a1. 841.16 3,291,888 12/1966 Meazzi et a1.841.16

HERMAN KARL SAALBACH, Primary Examiner PAUL L. GENSLER, AssistantExaminer US. Cl. X.R.

